I'm relatively new to ITIL, and I want to make sure I have an accurate picture of what ITIL is. I was hoping the experienced folks here could verify my current understanding.

It seems to me that:

ITIL defines a set of processes that should occur within a mature IT organisation in order to have adequate control over the delivery of IT services.

ITIL doesn't provide formal process definitions, though it does detail the key features that those processes should have. (e.g.: inputs, outputs and roles).

ITIL doesn't define methods for moving from an organisation's current maturity level to the ideal maturity level. i.e.: there is no material detailing which process group should be tackled first, or how an organisation could self-assess to determine which areas would benefit the most from the introduction of an ITIL-based process.

Is that accurate? Any corrections or further information is most welcome.